Abstract
Relating magnetotransport properties to specific spin textures at surfaces or interfaces is an intense field of research nowadays. Here, we investigate the variation of the electrical resistance of Ge(111) grown epitaxially on semi-insulating Si(111) under the application of an external magnetic field. We find a magnetoresistance term that is linear in current density and magnetic field , hence, odd in and , corresponding to a unidirectional magnetoresistance. At 15 K, for (or ) and , it represents 0.5% of the zero field resistance, a much higher value compared to previous reports on unidirectional magnetoresistance (UMR). We ascribe the origin of this magnetoresistance to the interplay between the externally applied magnetic field and the pseudomagnetic field generated by the current applied in the spin-splitted subsurface states of Ge(111). This unidirectional magnetoresistance is independent of the current direction with respect to the Ge crystal axes. It progressively vanishes, either using a negative gate voltage due to carrier activation into the bulk (without spin-splitted bands), or by increasing the temperature due to the Rashba energy splitting of the subsurface states lower than . We believe that UMR could be used as a powerful probe of the spin-orbit interaction in a wide range of materials.
- Received 4 June 2019
- Revised 4 September 2019
DOI:https://doi.org/10.1103/PhysRevLett.124.027201
© 2020 American Physical Society
Physics Subject Headings (PhySH)
Synopsis
Directionally Sensitive Magnetoresistance
Published 13 January 2020
A new experiment shows that the semiconductor germanium exhibits unidirectional magnetoresistance, which had previously only been seen in more exotic materials.
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